1. Technical Field
The present invention relates to an apparatus for generating a vacuum, and particularly relates to an apparatus for generating a vacuum in a suction head for engaging and moving a signature relative to a stack of signatures in a hopper.
2. Description of the Prior Art
It is known in the art to engage and move a signature relative to a stack of signatures in a hopper using one or more suction heads. Each suction head is connected by an air line to a source for generating a vacuum, such as a vacuum pump, which is remotely located relative to the suction head. Because the air lines have to be evacuated before a vacuum is pulled in each suction head, there is an inherent time delay between the initiation of the vacuum source and a vacuum being achieved at the suction head. Further, the air lines have to be blown down periodically to clean out paper dust which can become trapped in the vacuum system.